Your HVAC system’s performance isn’t the only factor in how well your home maintains its temperature. While it may be the first item to evaluate if it’s suddenly too hot or too cold in your home, there’s also a chance that something else could be causing the issue.
Another important factor in how well your home maintains its indoor temperature relates to insulation. Physical insulation layers, as well as seals around windows and doors, are designed to help keep your home comfortable, regardless of the temperature outside.
In this chapter, we’ll cover insulation basics, along with home insulation tips and ways to increase its effectiveness in your living space.
How Insulation Works
At a basic level, insulation works by slowing specific heat flows, including conductive, convective and radiant flows. It’s important to note that each insulation material works differently, which we will touch upon shortly.
What is conduction? Convection? Radiant heat? Understanding these terms is beneficial to learn how insulation can be improved if it’s lacking:
- Conduction refers to how heat moves through actual materials. For instance, sometimes an item that’s placed in a hot liquid can be heated enough to burn your hand if you pick it up. This is because the heat from the liquid has transferred to and through the object via conduction.
- Convection is how heat moves through the air and through liquids. Warm air is lighter, so it rises. Cool air is denser than warm air, so it sinks. This cycle of rising and sinking air is how convection develops and moves heat.
- Radiant heat travels in a straight line and heats solid pieces of matter in its path. This is why the sun shining on rocks and other objects causes those objects to be warm. This is different than conduction, which requires an object to be immersed or surrounded by a heated or cooled solution or type of matter.
As far as your home is concerned, an overriding principle to understand is that heat will always move from warmer spaces to cooler spaces. This means that when the weather is cooler outside, the heat inside your home will try to move to cooler spaces like to unheated areas of the home and to the outside.
On the other side of the equation, in the summer, warm air that’s outside will try to overtake the cooler spaces inside your home. The same thing happens in winter, but in reverse. In the winter, the cold air outside is not directly penetrating the inside. Instead, the warm air is escaping.
This constant act of trying to maintain a consistent temperature can be costly for you as a homeowner. Your HVAC system is trying to maintain a constant temperature, but warm and cool air are lost due to basic heating principles.
Your unit is designed to maintain the temperature you’ve set, but in some situations, it has to work harder than others. In this way, insulation works with your HVAC unit to help your home resist the natural flow of heat by providing a barrier.
Understanding R-Values in Insulation
At this point, you may be wondering how to seal your home in the most effective way possible to give your HVAC system a break while maintaining a consistent temperature. A concept that could be helpful in providing additional insight in this area relates to R-values.
If you’ve looked into insulation before or if you watch home improvement shows on television, you’ve probably heard the term R-value, though you may not be entirely familiar with what it means. R-values are number based, which makes the term sound complicated, but it’s easy to understand.
The R-value relates to a material designed to be an insulator’s resistance to heat flow. The higher the R-value is, the greater it will function as an insulator.
Every material designed to insulate a home has an assigned, individual R-value, which refers to the resistance found in a single layer of that material. This means that when various materials are layered or a single material is layered over itself, the R-values can be added together to make an even greater barrier. For instance, an insulator with R-38 can be layered with an insulator assigned R-30 to create a total R-value of R-68.
In the same way the numbers can be added, they can also be subtracted, though these numbers are more difficult to identify. If a material is compressed to fit into a space, the R-value could be reduced, and it could create less of a barrier than it was designed to.
Various climates across the country require different R-values in different areas of the home. When a new home is built, it must adhere to the R-value standards that are set by the government through different building codes. This means the insulation should adhere to the latest building codes in new homes. However, older homes, built to older building code standards, could need attention.
If you’re looking to install new insulation and are exploring options, the following numbers recommended by the U.S. Department of Energy for most zones in Pennsylvania could serve as a starting point. Because different areas of the home have different exposure levels to outdoor temperatures, they require different R-values to provide the highest level of protection.
- R-38 to R-60 in the attic
- R-30 to R-38 in cathedral ceilings
- R-13 to R-15 in any open cavities inside to adjacent to the home
- R-2.5 to R-6 in any sheathing used in walls inside or outside the home
- R-25 to R-30 in the floor
If you’ve discussed a remodel or have started searching for insulation options to install yourself, these guidelines could be beneficial. If you have questions about your home’s current insulation, how effective it may be or how you could improve it, it may be best to contact a professional.
Remember, an optimal level of insulation is the best defense against heat loss in the winter and heat intrusion in the summer. It can increase your comfort and decrease your heating and cooling expenses.
Types of Insulation Materials
If you’ve gone up into an older attic, you may be familiar with insulation. However, there are many types of insulation, and each is designed for different uses. They include:
- Blanket insulation. Blanket insulation fits between studs, joists and beams, making it ideal for unfinished walls, floors and ceilings. It’s made of various materials including fiberglass, mineral wool and plastic fibers. It’s known for being easy to install on your own and inexpensive.
- Concrete block insulation. Concrete block insulation is designed to insulate areas of exposed concrete blocks, which don’t do much to protect a home from outdoor temperatures. It’s composed of foam board that’s fitted around the blocks in unfinished walls and basements during new construction and major renovations. This insulation is best installed by a skilled contractor.
- Insulated concrete blocks. Insulated concrete blocks can be used on their own or in combination with concrete block insulation. They are filled with foam beads to increase the insulation potential of the blocks themselves, before additional insulation is applied.
- Reflective insulation systems. Reflective insulation systems are also ideal for installing on your own without the help of a professional. Designed to prevent downward flowing heat loss, reflective systems use foil-faced paper, plastic and other materials to provide extra insulation in areas that are traditionally hard to fill, including around joints and other spaces. They add an extra layer of insulation that requires very little space.
- Foam board insulation. Foam board insulation provides high R-value protection in a relatively thin piece of material. It’s most frequently used in unfinished walls, floors, ceilings and unvented areas of roofing. Because it’s flammable, it must be coated with gypsum or another fire retardant to meet building code regulations or with weatherproof facing when exposed to the elements.
- Loose or blown-in insulation. Loose or blown-in insulation is easy to handle on your own. It’s composed of cellulose, fiberglass or mineral wool and is blown into place using special equipment that can be rented. For these reasons, it’s considered to be the best insulation for attic spaces that need extra protection.
- Rigid fiber insulation. Rigid fiber insulation provides an extra layer of insulation in areas that require resistance to extreme heat – around duct work, for example. Generally, this insulation is installed by HVAC professionals either on job sites or when systems are assembled at the plant. It’s made of fiberglass and mineral wool, like other types of insulation.
- Spray foam insulation. Spray foam insulation comes in ready-to-use spray bottles that do not require extra equipment. It can be easily applied by non-professionals to existing areas that require extra insulation.
R-values are extremely dependent upon proper installation procedures. Therefore, it may be wise to leave large insulation jobs to the professionals.
If you decide to hire a professional insulation installer:
- Ask around for recommendations from friends and family members. You can also search online.
- Ask for written estimates for your project to ensure the price you’ve been quoted is reasonable.
- Ask about the R-value needed for your project – this should be fairly consistent between multiple contractors.
- Ask for references and an estimated project timeline.
If you’re interested in increasing your home’s insulation on your own, take a look at exposed areas that you can access easily. Look for gaps in existing insulation. These are areas you may be able to improve upon.
Also, inspect the areas you can access for compression. Over time, compressed materials may be less effective, so adding another layer could increase your home’s overall protection without too much effort or cost.
If you decide to proceed with a DIY installation, be sure to read and follow all instructions provided by the manufacturer, along with paying attention to any safety precautions that may be listed. Check with your local building code inspector to learn what permits you may need to obtain and if there are fire codes you should be aware of. Remember that safety is of the utmost importance for insulation installation and all other home projects.
Other Ways to Seal Your Home
While it’s easy to focus on insulation as a top line of defense for your home, it’s not the only one. Another major cause of heat loss and heat intrusion is drafts. Doors and windows are harder to seal because they’re designed to open and close. This makes them a common problem area.
If you’re unsure of whether a door or window is allowing a draft to enter your home, hold a lit incense stick near its outer edge, which is a good practice for all windows and doors in your home. Then, watch how the smoke moves. If it seems to be moving away from the window or door in question, there’s likely a draft coming from that source.
How to Seal Air Leaks in Your Home
If you find an air leak that’s allowing drafts to enter through a door or window, you can take steps to seal it on your own in a cost-effective manner.
Two potential solutions include caulking and weather-stripping. Weather-stripping generally costs around $12 for 17 feet, and caulking is less expensive. Each of these solutions works to seal areas where the window or door comes into contact with the home, the most common source of drafts. Caulking uses a clay-like material that comes in a tube and can be messier, while weather-stripping provides the same protection in a “roll-out” format.
If the draft is coming from the bottom of the door, a threshold gasket can be replaced for around $15. Or, a door sweep that attaches to the bottom of the door can be added for around $10. These devices slide on to the bottom of the door to create a better seal when the door is closed. Over time, seals can become less tight, leading to drafts. Door sweeps and threshold gaskets provide possible solutions.
If these options are not viable, the drafts are widespread or the home is aging, it may be necessary to install new doors and windows. While this will cost more, it may help with the overall energy efficiency of your home, saving you money in heating and cooling costs in the long run.
For small, single-point leaks, caulk may seal them effectively. If an entire edge of a window or its frame needs attention, weather-stripping may be a better option.
To begin the process, select the weather-stripping that is most appropriate for the door or window you’ll be applying it to. It should be able to withstand friction (depending on how frequently the door or window is used), various temperatures, and the wear and tear that may accompany its location. Your selection should be thick enough to create a seal when the door or window is closed, but still allow it to open freely for regular use.
If a space is shaped irregularly, it may require a few different types of weather-stripping. Various options include:
Select an option that will meet your needs and blend in with the space where it will be applied.
Once you’ve decided what will be appropriate for your project, it’s time to get started. Follow the tips below for installing weather-stripping to better protect your home from drafts:
- Determine the amount of weather-stripping you’ll need for your project. Be sure to measure any doors and windows you’ll be applying it to and add approximately 5% to 10% to your measurements to be sure you purchase enough. Remember, weather stripping can be applied around an entire doorjamb, or between the sash and the frame of a drafty window.
- Read the directions. Like most home improvement projects, various types of weather-stripping have different techniques for installation and application.
- Be sure the conditions are right. Weather-stripping should be applied to clean, dry surfaces when the weather is above 20 degrees Fahrenheit. Be sure to clean any dust and dirt that could come between the door or window and the weather-stripping for optimal fit.
- Take your time. Before making any cuts, measure two or three times. It never hurts to be overly cautious when working on a project for your home. That level of caution could save you time, frustration and money.
- Be prepared. Weather-stripping is designed to create a snug fit that compresses when the door or window in question closes. If it feels tight, that’s okay.
- Focus on a continuous edge. Each edge should feature one solid strip of weather-stripping, which should meet tightly with other strips at all corners.
If a door or window is too difficult to shut after you’ve applied the weather-stripping, you may need to find a thinner option. If you’re working on multiple doors and/or windows, test one before moving on to the others.
Other Options for Reducing Drafts
Replacing doors and windows, updating insulation and applying caulk or weather-stripping aren’t the only ways to reduce drafts in your home. Other options that are simple and cost effective include:
- Adding draperies. Something as simple as adding draperies can reduce the heat loss in your home by up to 25%.
- Purchasing window panels or storm windows for the winter. These are temporary and contain an insulating material inside a frame that seals against the interior side of a window. They use magnets or Velcro, so they can be removed in warmer temperatures.
- Installing window films. Window films work by sealing a window with a clear plastic that shrinks to fit the window when heat — such as from a hair dryer — is applied. They seal the entire window without obstructing outdoor views, but do prevent the window from opening until they are removed.
Any measure you take to reduce drafts in your home could help save on heating costs while prolonging the life of your HVAC system by allowing it to work less. No effort is too small in this regard.
Your home should be comfortable. If your HVAC unit isn’t operating properly, evaluate your home’s insulation, as well as sources of drafts. If you’re unsure of where to start, consider speaking with a professional contractor sooner rather than later.
Read our other chapters
Why Maintenance Matters and How to Budget for It
Plumbing Maintenance — From Snaking a Main Drain to Dealing with Hard Water Clogs
Well Maintenance — Water Well Maintenance Starts With Understanding Groundwater Basics
Septic Tank Maintenance — Preventative Care for Your Tank and Spotting Warning Signs
Sewer Line Maintenance — From Understanding How Systems Work to Spotting Clogs
HVAC System Maintenance — Keeping Your Home Comfortable Throughout the Year
Insulation — Better Insulating Your Home and Preventing and Addressing Drafts
Home Exterior Maintenance — Saving Costs by Identifying Seasonal Tasks
Home Improvement Ideas — Adding Value to Your Home and Getting a Return on Your Investment
Download all chapters as a PDF.